New York Attorney General Eric Schneiderman is investigating services offered by stock exchanges that he alleges give certain high-speed investors an unfair advantage by getting early access to data. `

Schneiderman said during a speech Tuesday that he was urging stock exchanges to consider curbing such features and adopting proposed safeguards to ensure investors are competing on an equal playing field.

The features in question include "co-location," which allow traders to locate their computer servers within exchanges' data centers, and services that provide extra network bandwidth to high-frequency traders.

"These valuable advantages give high-frequency traders a leg up on the rest of the market," Schneiderman said in the speech at New York Law School.

Schneiderman's proposal is the latest in a continuing probe of Wall Street activities that allow investors and other market participants to gain a competitive edge through the early release of market-moving data, a practice he calls "insider trading 2.0."

In January, BlackRock, the world's largest asset-management firm, agreed to terminate a survey program that asked stock analysts for details about companies that they cover. Schneiderman alleged the program enabled BlackRock to get information from analysts before it was disseminated more widely to other investors.

BlackRock said its survey sought public information and that it ended the program to avoid the appearance of impropriety.

Last month Schneiderman announced that 18 brokerage firms agreed to stop participating in such survey programs.

Business Wire, a unit of Berkshire Hathaway, also announced last month that it would stop giving high-speed traders direct access to corporate earnings and other market-moving information following conversations with Schneiderman's office.

In the case of exchanges, Schneiderman said his office is concerned about their dealings with high-frequency traders, who use sophisticated algorithms to quickly crunch data enabling them to rapidly trade stocks. The attorney general says he is concerned exchanges are giving special access to their data and enabling some investors to unfairly reap larger profits than others.

"If you move enough money in and out quickly, you can make billions of dollars per year," Schneiderman said.

Peter Nabicht, a senior adviser for Modern Markets Initiative, a trade group for high-frequency traders, said co-location and direct feeds of market data are "available to all market participants, including brokers trading on behalf of investors."

"In the interest of fairness, not only are these services available, they promote efficiency and transparency," Nabicht said in a statement, adding that it is "critical" such services remain available "on fair and equal terms."

Schneiderman said one solution to level the playing field would be to put in place a sort of "speed bump" in which trading orders would be processed in batches. The approach, which has been proposed by University of Chicago economists, would ensure that price, not timing, would be the "deciding factor in who obtains a trade, Schneiderman said. Such a move could also make it less attractive for investors to route their orders through alternative venues, such as "dark pools," which Schneiderman said are "less regulated" and are "far less transparent."